Inductor built-in substrate

ABSTRACT

An inductor built-in substrate includes a core substrate having openings and first through holes, a magnetic resin filled in the openings and having second through holes, first through-hole conductors formed in the first through holes respectively such that each of the first through-hole conductors includes a metal film, and second through-hole conductors formed in the second through holes respectively such that each of the second through-hole conductors includes a metal film and that the metal film in each of the first through-hole conductors has a thickness that is greater than a thickness of the metal film in each of the second through-hole conductors.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is based upon and claims the benefit of priorityto Japanese Patent Application No. 2019-078600, filed Apr. 17, 2019, theentire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an inductor built-in substrate that hasan inductor built therein.

Description of Background Art

Japanese Patent Application Laid-Open Publication No. 2016-197624describes a method for manufacturing an inductor component built in awiring substrate. The entire contents of this publication areincorporated herein by reference.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, an inductor built-insubstrate includes a core substrate having openings and first throughholes, a magnetic resin filled in the openings and having second throughholes, first through-hole conductors formed in the first through holesrespectively such that each of the first through-hole conductorsincludes a metal film, and second through-hole conductors formed in thesecond through holes respectively such that each of the secondthrough-hole conductors includes a metal film and that the metal film ineach of the first through-hole conductors has a thickness that isgreater than a thickness of the metal film in each of the secondthrough-hole conductors.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1A is a cross-sectional view of an inductor built-in substrateaccording to an embodiment of the present invention;

FIG. 1B is a plan view of through-hole lands;

FIG. 1C is an enlarged view of a core substrate of the inductor built-insubstrate;

FIGS. 2A-2E are process diagrams illustrating a method for manufacturingan inductor built-in substrate according to an embodiment of the presentinvention;

FIGS. 3A-3D are process diagrams illustrating the method formanufacturing an inductor built-in substrate according to theembodiment; and

FIGS. 4A-4C are process diagrams illustrating the method formanufacturing an inductor built-in substrate according to theembodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments will now be described with reference to the accompanyingdrawings, wherein like reference numerals designate corresponding oridentical elements throughout the various drawings.

FIG. 1A illustrates a cross-sectional view of an inductor built-insubstrate 10 of an embodiment that has an inductor built therein. Theinductor built-in substrate 10 has a core substrate 30 that is formed toinclude: an insulating base material 20 that has a first surface (F) anda second surface (S) on an opposite side with respect to the firstsurface (F); a first conductor layer (conductor circuit) (58F) on thefirst surface (F) of the insulating base material; a second conductorlayer (58S) on the second surface (S) of the insulating base material;and through-hole conductors 36 that connect the first conductor layer(58F) and the second conductor layer (58S) to each other. The coresubstrate 30 has a first surface (F) and a second surface (S) on anopposite side with respect to the first surface (F). The first surface(F) of the core substrate 30 and the first surface (F) of the insulatingbase material 20 are the same surface, and the second surface (S) of thecore substrate 30 and the second surface (S) of the insulating basematerial 20 are the same surface. The insulating base material 20 isformed of a resin such as an epoxy resin and a core material 14 such asa glass cloth for reinforcement. The insulating base material 20 mayfurther contain inorganic particles such as silica particles.

The inductor built-in substrate 10 further has an upper side build-uplayer (450F) formed on the first surface (F) of the core substrate 30.The upper side build-up layer (450F) includes: an insulating layer(450A) formed on the first surface (F) of the core substrate 30; aconductor layer (458A) formed on the insulating layer (450A); and viaconductors (460A) penetrating the insulating layer (450A) and connectingthe first conductor layer (58F) and the conductor layer (458A) to eachother. The upper side build-up layer (450F) further includes: aninsulating layer (450C) formed on the insulating layer (450A) and theconductor layer (458A); a conductor layer (458C) formed on theinsulating layer (450C); and via conductors (460C) penetrating theinsulating layer (450C) and connecting the conductor layer (458A) andthe conductor layer (458C) to each other.

The inductor built-in substrate 10 further has a lower side build-uplayer (450S) formed on the second surface (S) of the core substrate 30.The lower side build-up layer (450S) includes: an insulating layer(450B) formed on the second surface (S) of the core substrate 30; aconductor layer (458B) formed on the insulating layer (450B); and viaconductors (460B) penetrating the insulating layer (450B) and connectingthe second conductor layer (58S) and the conductor layer (458B) to eachother. The lower side build-up layer (450S) further includes: aninsulating layer (450D) formed on the insulating layer (450B) and theconductor layer (458B); a conductor layer (458D) formed on theinsulating layer (450D): and via conductors (460D) penetrating theinsulating layer (450D) and connecting the conductor layer (458B) andthe conductor layer (458D) to each other.

The inductor built-in substrate of the embodiment further includes asolder resist layer (470F) having openings (471F) formed on the upperside build-up layer (450F) and a solder resist layer (470S) havingopenings (471S) formed on the lower side build-up layer (450S).

Upper surfaces of the conductor layers (458C, 458D) or the viaconductors (460C, 460D) exposed from the openings (471F, 471S) of thesolder resist layers (470F, 470S) function as pads. A protective film472 formed of Ni/Au, Ni/Pd Au, Pd/Au, OSP, or the like is formed on eachof the pads. Solder bumps (476F, 476S) are respectively formed on theprotective films. An IC chip (not illustrated in the drawings) ismounted on the inductor built-in substrate 10 via the solder bumps(476F) formed on the upper side build-up layer (450F). The inductorbuilt-in substrate 10 is mounted on a motherboard via the solder bumps(476S) that are formed on the lower side build-up layer (450S).

FIG. 1C illustrates an enlarged view of a portion of the core substrate30 in FIG. 1A. In the core substrate 30, the through-hole conductors 36connecting the first conductor layer (58F) and the second conductorlayer (58S) to each other include first through-hole conductors (36A)that are respectively formed in first through holes (20 a) penetratingthe core substrate 30 and second through-hole conductors (36B) that arerespectively formed in second through holes (18 b) of a magnetic resin18 filled in openings (20 b) of the core substrate 30. A diameter (da)of each of the first through holes (20 a) and a diameter (db) of each ofthe second through holes (18 b) are substantially equal to each other. Aresin filler 16 is filled inside the first through-hole conductors (36A)and the second through-hole conductors (36B), and through-hole lands(58FR) are formed of cover plating. The through-hole lands (58FR)include first through-hole lands (58FRA) respectively formed on thefirst through-hole conductors (36A) and second through-hole lands(58FRB) respectively formed on the second through-hole conductors (36B).

FIG. 1B is a plan view of a first through-hole land (58FRA) formed on afirst through-hole conductor (36A) and a second through-hole land(58FRB) formed on a second through-hole conductor (36B). The firstthrough-hole land (58FRA) is concentrically formed with the firstthrough-hole conductor (36A), and the second through-hole land (58FRB)is concentrically formed with the second through-hole conductor (36B). Adiameter (Da) of the first through-hole land (58FRA) and a diameter (Db)of the second through-hole land (58FRB) are substantially equal to eachother. The first through-hole land (58FRA) and the second through-holeland (58FRB) are connected to each other by the first conductor layer(circuit pattern) (58F). The diameter (Db) of the second through-holeland (58FRB) is smaller than a diameter (DB) of each of the openings (20b) in which the magnetic resin 18 is filled. That is, the secondthrough-hole land (58FRB) does not spread from the magnetic resin 18 tothe insulating base material 20.

The magnetic resin 18 contains an iron oxide filler (magnetic particles)and a resin such as an epoxy resin. Examples of the magnetic particlesinclude iron oxide fillers such as FeO, Fe₂O₃, and Fe₃O₄ particles. Acontent of the iron oxide filler in the magnetic resin is preferably 60%by weight or more. From a point of view that the content of the ironoxide filler can be increased and magnetic permeability and heatconductivity can be increased, particle sizes of the iron oxide fillerare desirably non-uniform.

As illustrated in FIG. 1C, a first through-hole conductor (36A) formedin a first through hole (20 a) penetrating the core substrate 30 is incontact with the first through hole (20 a). The first through-holeconductor (36A) includes a second electroless plating film 32 on thefirst through hole (20 a), and a second electrolytic plating film 34 onthe second electroless plating film 32. A second through-hole conductor(36B) formed in a second through hole (18 b) penetrating the magneticresin 18 is in contact with the second through hole (18 b). The secondthrough-hole conductor (36B) includes a second electroless plating film32 on the second through hole (18 b), and a second electrolytic platingfilm 34 on the second electroless plating film 32. A thickness (ta) ofthe second electroless plating film 32 and the second electrolyticplating film 34 that form the first through-hole conductor (36A) islarger than a thickness (tb) of the second electroless plating film 32and the second electrolytic plating film 34 that form the secondthrough-hole conductor (36B). When the thickness (ta) of the firstthrough-hole conductor (36A) formed in the first through hole (20 a) ofthe insulating base material 20 having a low heat conductivity is largerthan the thickness (tb) of the second through-hole conductor (36B)formed in the second through hole (18 b) of the magnetic resin 18 havinga high heat conductivity, a balance in heat dissipation between thefirst through-hole conductor (36A) and the second through-hole conductor(36B) is adjusted.

The first through-hole lands (58FRA) and the first conductor layer (58F)on the insulating base material 20 are each formed of the copper foil 22as a lowermost layer, the first electroless plating film (24 m) on thecopper foil 22, the first electrolytic plating film (24 d) on the firstelectroless plating film (24 m), the second electroless plating film 32on the first electrolytic plating film (24 d), the second electrolyticplating film 34 on the second electroless plating film 32, the thirdelectroless plating film 35 on the second electrolytic plating film 34,and the third electrolytic plating film 37 on the third electrolessplating film 35. The second through-hole lands (58FRB) and the firstconductor layer (58F) on the magnetic resin 18 are each formed of thefirst electroless plating film (24 m) as a lowermost layer, the firstelectrolytic plating film (24 d) on the first electroless plating film(24 m), the second electroless plating film 32 on the first electrolyticplating film (24 d), the second electrolytic plating film 34 on thesecond electroless plating film 32, the third electroless plating film35 on the second electrolytic plating film 34, and the thirdelectrolytic plating film 37 on the third electroless plating film 35.The first electroless plating film (24 m) and the first electrolyticplating film (24 d) form a shield layer 24. A thickness (tA) of thefirst through-hole lands (58FRA) and the first conductor layer (58F) onthe insulating base material 20 is larger than a thickness (tB) of thesecond through-hole lands (58FRB) and the first conductor layer (58F) onthe magnetic resin 18 by a thickness of the copper foil 22. When thethickness (tA) of the first through-hole lands (58FRA) formed on theinsulating base material 20 having a low heat conductivity is largerthan the thickness (tB) of the second through-hole lands (58FRB) formedon the magnetic resin 18 having a high heat conductivity by thethickness of the copper foil 22 having a high heat conductivity, abalance in heat dissipation between the first through-hole conductors(36A) and the second through-hole conductors (36B) is adjusted.

In the core substrate 30 of the embodiment, the first conductor layer(58F) (connection pattern (58FL)) and the second conductor layer (58S)(connection pattern (58SL)) which are connected to each other via thesecond through-hole conductors (36B) formed in the magnetic resin 18illustrated in FIG. 1A are arranged in a helical shape (a spiral shapealong an axis in a direction parallel to the front and back surfaces ofthe core substrate), and together with the second through-holeconductors (36B) form an inductor 59.

In the inductor built-in substrate 10 of the embodiment, the firstconductor layer (58F) and the second conductor layer (58S) are formed onthe surfaces of the core substrate 30, and the second through-holeconductors (36B) connecting the first conductor layer (58F) and thesecond conductor layer (58S) to each other are directly formed in thesecond through holes (18 b) penetrating the magnetic resin 18.Therefore, a ratio of a magnetic material in the inductor built-insubstrate 10 is increased and an inductance can be increased.

Method for Manufacturing Inductor Built-In Substrate

A method for manufacturing an inductor built-in substrate according toan embodiment of the present invention is illustrated in FIGS. 2A-4C.

A substrate (20 z) is prepared which is formed of a copper-cladlaminated plate which is formed by laminating a copper foil 22 on bothsides of the insulating base material 20 (FIG. 2A). The openings (20 b)for filling the magnetic resin therein are formed in the insulating basematerial 20 (FIG. 2B). A resin paste containing an iron oxide filler(magnetic particles) in an amount of 90% by weight and an epoxy resin isvacuum-printed in the openings (20 b). The resin paste is temporarilycured (semi-cured) at a temperature at which a viscosity of the resinpaste is 2 or less times that at a normal temperature, and a temporarilycured magnetic resin (18β) is formed (FIG. 2C).

On a surface of the insulating base material 20 and a surface of thetemporarily cured magnetic resin (18β) exposed from the openings (20 b),a first electroless plating film (24 m) is formed by an electrolessplating treatment, and a first electrolytic plating film (24 d) isformed by an electrolytic plating treatment (FIG. 2D). The firstelectroless plating film (24 m) and the first electrolytic plating film(24 d) form a shield layer 24.

The first through holes (20 a) are formed in the insulating basematerial 20 by mechanical drilling, laser processing, or the like (FIG.2E). Thereafter, the first through holes (20 a) are subjected to adesmear treatment using a chemical solution. During the desmeartreatment, the temporarily cured magnetic resin (18β) covered by ashield layer 24 formed by the first electroless plating film (24 m) andthe first electrolytic plating film (24 d) is not affected by thechemical solution. The iron oxide filler on the surface of thetemporarily cured magnetic resin (18β) is not affected by the desmeartreatment.

The second through holes (18 b) are formed in the temporarily curedmagnetic resin (18β) by mechanical drilling, laser processing, or thelike. In this embodiment, since the iron oxide filler is contained in anamount of 90% by weight, through hole formation after fully curing isnot easy. However, since the through holes are formed before fullycuring, the through holes can be easily formed. The magnetic materiallayer in a temporarily cured state is heated to cause the resincontained therein to crosslink, and thereby, the magnetic material layeris fully cured to form the magnetic resin 18 (FIG. 3A). Here, heating isperformed at 150° C.-190° C. for one hour. By high-pressure waterwashing, processing smear occurred during through hole formation isremoved (FIG. 3B). Desmearing is performed using an alkaline agent.However, there is a risk that an alkaline agent may cause the iron oxidefiller contained in the magnetic resin 18 to fall off during a processin which the resin is swelled and peeled off. Therefore, here,high-pressure water washing is performed. On the first electrolyticplating film (24 d) on the surfaces of the insulating base material 20and the magnetic resin 18 and on surfaces of the first through holes (20a) and the second through holes (18 b), a second electroless platingfilm 32 is formed by an electroless plating treatment and a secondelectrolytic plating film 34 is formed by an electrolytic platingtreatment. By the second electroless plating film 32 and the secondelectrolytic plating film 34, the first through-hole conductors (36A)are formed in the first through holes (20 a) and the second through-holeconductors (36B) are formed in the second through holes (18 b) (FIG.3C).

The resin filler 16 is filled inside the first through-hole conductors(36A) formed in the first through holes (20 a) and inside the secondthrough-hole conductors (36B) formed in the second through holes (18 b),and the surfaces of the core substrate 30 are polished (FIG. 3D). Athird electroless plating film 35 is formed by electroless plating onthe second electrolytic plating film 34 and on exposed surfaces of theresin filler 16, and a third electrolytic plating film 37 is formed onthe third electroless plating film 35 (FIG. 4A). An etching resist 54 ofa predetermined pattern is formed on the third electrolytic plating film37 (FIG. 4B).

The third electrolytic plating film 37, the third electroless platingfilm 35, the second electrolytic plating film 34, the second electrolessplating film 32, the first electrolytic plating film (24 d), the firstelectroless plating film (24 m), and the copper foil 22 exposed from theetching resist 54 are removed, and thereafter, the etching resist isremoved, and the first conductor layer (58F), the second conductor layer(58S) are formed and the core substrate 30 is completed (FIG. 4C). Thefirst conductor layer (58F) and the second conductor layer (58S) on theinsulating base material 20 and the first through-hole lands (58FRA) onthe first surface side of the first through-hole conductors (36A) andfirst through-hole lands (58SRA) on the second surface side of the firstthrough-hole conductors (36A) are each formed of the copper foil 22 as alowermost layer, the first electroless plating film (24 m) on the copperfoil 22, the first electrolytic plating film (24 d) on the firstelectroless plating film (24 m), the second electroless plating film 32on the first electrolytic plating film (24 d), the second electrolyticplating film 34 on the second electroless plating film 32, the thirdelectroless plating film 35 on the second electrolytic plating film 34,and the third electrolytic plating film 37 on the third electrolessplating film 35. The first conductor layer (58F) and the secondconductor layer (58S) on the magnetic resin 18 and the secondthrough-hole lands (58FRB) on the first surface side of the secondthrough-hole conductors (36B) and second through-hole lands (58SRB) onthe second surface side of the second through-hole conductors (36B) areeach formed of the first electroless plating film (24 m), the firstelectrolytic plating film (24 d) on the first electroless plating film(24 m), the second electroless plating film 32 on the first electrolyticplating film (24 d), the second electrolytic plating film 34 on thesecond electroless plating film 32, the third electroless plating film35 on the second electrolytic plating film 34, and the thirdelectrolytic plating film 37 on the third electroless plating film 35.

The upper side build-up layer (450F), the lower side build-up layer(450S), the solder resist layers (470F, 470S), and the solder bumps(476F, 476S) are formed on the core substrate 30 using knownmanufacturing methods (FIG. 1A).

In the method for manufacturing the inductor built-in substrate of theembodiment, the second through-hole conductors (36B) formed of thesecond electroless plating film 32 and the second electrolytic platingfilm 34 are formed in the second through holes (18 b) of the magneticresin 18. Therefore, the volume of the magnetic resin 18 of the inductorbuilt-in substrate 10 can be increased, and the inductance can beincreased.

In Japanese Patent Application Laid-Open Publication No. 2016-197624, amagnetic material is accommodated in a resin layer, through-holeconductors are provided in the resin layer, and the through-holeconductors are prevented from being in contact with the magneticmaterial.

In Japanese Patent Application Laid-Open Publication No. 2016-197624,since the through-hole conductors are arranged in the resin layer, it isthought that a ratio of the magnetic material with respect to a size ofthe inductor component is low and it is difficult to increase aninductance.

An inductor built-in substrate according to an embodiment of the presentinvention has high heat dissipation performance, is small in size, andhas a large inductance.

An inductor built-in substrate according to an embodiment of the presentinvention includes: a core substrate in which openings and first throughholes are formed; a magnetic resin filled in the openings and havingsecond through holes; first through-hole conductors formed of metalfilms formed in the first through holes; and second through-holeconductors formed of metal films formed in the second through holes. Themetal film of the first through-hole conductor has a larger thicknessthan the metal film of the second through-hole conductor.

In an inductor built-in substrate according to an embodiment of thepresent invention, the second through-hole conductor formed of a metalfilm is directly formed in the second through hole of the magneticresin. Therefore, a volume of the magnetic resin of an inductorcomponent can be increased, and an inductance can be increased. Thethickness of the first through-hole conductor formed in the coresubstrate having low heat dissipation performance is larger than thethickness of the second through-hole conductor formed in the magneticresin having high heat dissipation performance, and heat dissipationperformance is improved.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

What is claimed is:
 1. An inductor built-in substrate, comprising: acore substrate having a plurality of openings and a plurality of firstthrough holes; a magnetic resin filled in the openings and having aplurality of second through holes; a plurality of first through-holeconductors formed in the plurality of first through holes respectivelysuch that each of the first through-hole conductors comprises a metalfilm; and a plurality of second through-hole conductors found in theplurality of second through holes respectively such that each of thesecond through-hole conductors comprises a metal film and that the metalfilm in each of the first through-hole conductors has a thickness thatis greater than a thickness of the metal film in each of the secondthrough-hole conductors.
 2. The inductor built-in substrate according toclaim 1, wherein the plurality of first through-hole conductors isformed such that the metal film in each of the first through-holeconductors includes an electroless plating film and an electrolyticplating film, and the plurality of second through-hole conductors isformed such that the metal film in each of the second through-holeconductors includes an electroless plating film and an electrolyticplating film.
 3. The inductor built-in substrate according to claim 2,wherein the magnetic resin includes an iron oxide filler in an amount of60% by weight or more.
 4. The inductor built-in substrate according toclaim 2, further comprising: a plurality of first through-hole landsformed on the core substrate such that each of the first through-holelands includes a lowermost layer comprising a metal foil; and aplurality of second through-hole lands formed on the magnetic resin suchthat each of the second through-hole lands includes a lowermost layercomprising a plating film.
 5. The inductor built-in substrate accordingto claim 4, wherein the plurality of first through-hole lands is formedsuch that each of the first through-hole lands includes the metal filmextending from a respective one of the first through-hole conductors,and a shield layer formed on a core substrate side of the metal film,and the plurality of second through-hole lands is formed such that eachof the second through-hole lands includes the metal film extending froma respective one of the second through-hole conductors, and a shieldlayer formed on a magnetic resin side of the metal film.
 6. The inductorbuilt-in substrate according to claim 5, wherein the plurality of firstthrough-hole lands is formed such that the shield layer in each of thefirst through-hole lands includes an electroless plating film and anelectrolytic plating film, and the plurality of second through-holelands is formed such that the shield layer in each of the secondthrough-hole lands includes an electroless plating film and anelectrolytic plating film.
 7. The inductor built-in substrate accordingto claim 3, further comprising: a plurality of first through-hole landsformed on the core substrate such that each of the first through-holelands includes a lowermost layer comprising a metal foil; and aplurality of second through-hole lands formed on the magnetic resin suchthat each of the second through-hole lands includes a lowermost layercomprising a plating film.
 8. The inductor built-in substrate accordingto claim 7, wherein the plurality of first through-hole lands is formedsuch that each of the first through-hole lands includes the metal filmextending from a respective one of the first through-hole conductors,and a shield layer formed on a core substrate side of the metal film,and the plurality of second through-hole lands is formed such that eachof the second through-hole lands includes the metal film extending froma respective one of the second through-hole conductors, and a shieldlayer formed on a magnetic resin side of the metal film.
 9. The inductorbuilt-in substrate according to claim 8, wherein the plurality of firstthrough-hole lands is formed such that the shield layer in each of thefirst through-hole lands includes an electroless plating film and anelectrolytic plating film, and the plurality of second through-holelands is formed such that the shield layer in each of the secondthrough-hole lands includes an electroless plating film and anelectrolytic plating film.
 10. The inductor built-in substrate accordingto claim 1, wherein the magnetic resin includes an iron oxide filler inan amount of 60% by weight or more.
 11. The inductor built-in substrateaccording to claim 10, further comprising: a plurality of firstthrough-hole lands formed on the core substrate such that each of thefirst through-hole lands includes a lowermost layer comprising a metalfoil; and a plurality of second through-hole lands formed on themagnetic resin such that each of the second through-hole lands includesa lowermost layer comprising a plating film.
 12. The inductor built-insubstrate according to claim 11, wherein the plurality of firstthrough-hole lands is formed such that each of the first through-holelands includes the metal film extending from a respective one of thefirst through-hole conductors, and a shield layer formed on a coresubstrate side of the metal film, and the plurality of secondthrough-hole lands is formed such that each of the second through-holelands includes the metal film extending from a respective one of thesecond through-hole conductors, and a shield layer formed on a magneticresin side of the metal film.
 13. The inductor built-in substrateaccording to claim 12, wherein the plurality of first through-hole landsis formed such that the shield layer in each of the first through-holelands includes an electroless plating film and an electrolytic platingfilm, and the plurality of second through-hole lands is formed such thatthe shield layer in each of the second through-hole lands includes anelectroless plating film and an electrolytic plating film.
 14. Theinductor built-in substrate according to claim 1, further comprising: aplurality of first through-hole lands formed on the core substrate suchthat each of the first through-hole lands includes a lowermost layercomprising a metal foil; and a plurality of second through-hole landsformed on the magnetic resin such that each of the second through-holelands includes a lowermost layer comprising a plating film.
 15. Theinductor built-in substrate according to claim 14, wherein the pluralityof first through-hole lands is formed such that each of the firstthrough-hole lands includes the metal film extending from a respectiveone of the first through-hole conductors, and a shield layer formed on acore substrate side of the metal film, and the plurality of secondthrough-hole lands is formed such that each of the second through-holelands includes the metal film extending from a respective one of thesecond through-hole conductors, and a shield layer formed on a magneticresin side of the metal film.
 16. The inductor built-in substrateaccording to claim 15, wherein the plurality of first through-hole landsis formed such that the shield layer in each of the first through-holelands includes an electroless plating film and an electrolytic platingfilm, and the plurality of second through-hole lands is formed such thatthe shield layer in each of the second through-hole lands includes anelectroless plating film and an electrolytic plating film.
 17. Theinductor built-in substrate according to claim 14, wherein the pluralityof first through-hole lands is formed such that each of the firstthrough-hole lands includes a shield layer, and the plurality of secondthrough-hole lands is formed such that each of the second through-holelands includes a shield layer.
 18. The inductor built-in substrateaccording to claim 1, wherein the plurality of first through holes andthe plurality of second through holes are formed such that a diameter ofeach of the first through holes is substantially equal to a diameter ofeach of the second through holes.
 19. The inductor built-in substrateaccording to claim 1, wherein the plurality of first through-holeconductors is formed such that a resin filler is filling inside each ofthe first through-hole conductors, and the plurality of secondthrough-hole conductors is formed such that a resin filler is fillinginside each of the second through-hole conductors.
 20. The inductorbuilt-in substrate according to claim 1, further comprising: a firstconductor layer formed on the core substrate such that the firstconductor layer includes a plurality of first through-hole lands formedon the core substrate; and a second conductor layer formed on themagnetic resin such that the second conductor layer includes a pluralityof second through-hole lands formed on the magnetic resin, wherein thefirst and second conductor layers are formed such that a thickness ofthe first conductor layer and the first through-hole lands on the coresubstrate is greater than a thickness of the second conductor layer andthe second through-hole lands on the magnetic resin.